The external skins of many aircraft are formed from a number of panels made of a composite material. This composite material may be a polymer matrix reinforced with fibres such as carbon or glass fibres.
Typically, aircraft panels are produced by curing layers of composite material to produce an initial aircraft panel. The initial aircraft panel is then inspected and further layers of composite material are added to the initial aircraft panel where additional thickness is required. The initial panel and added layers are re-cured to produce a modified aircraft panel. This process of inspection, adding additional layers of composite material, and re-curing is iteratively performed until the aircraft panel is as desired. This production process tends to be imprecise and time-consuming due, at least in part, to the unpredictability of the amount by which the thickness of a layer of composite material varies during curing.
Many conventionally produced aircraft panels do not conform to the shape of an aircraft airframe to which they are to be attached. Filler material, for example liquid shim, may have to be applied to fill gaps between the aircraft panel and the airframe. This is typically a time-consuming and costly process, and may add considerable excess weight to an aircraft.